PA-99-N2
{{Short description|Microlensing event in the constellation Andromeda}}
{{Starbox begin
|name=PA-99-N2
}}
{{Starbox observe|constell=Andromeda|ra={{RA|00|44|20.89{{cite simbad|title=MEGA-ML 7|access-date=3 June 2018}}}}|dec={{DEC|+41|28|44.6}}|epoch=J2000}}
{{Starbox astrometry
|no_heading=
|component=
|component1=|radial_v=|total_v=|prop_mo_ra=|prop_mo_dec=|parallax=|p_error=|pm_footnote=
|dist_ly=2,200,000|dist_pc=670,000}}
{{Starbox reference
|Simbad=PA+99-N2
}}
{{Starbox end}}
{{infobox astronomical event
|epoch=J2000
|ra={{RA|00|44|20.89}}{{cite simbad|title=MEGA-ML 7|access-date=3 June 2018}}
|distance=2,200,000 ly (670,000 pc)
}}
PA-99-N2 is a microlensing event detected in the direction of the Andromeda Galaxy in 1999.
Explanations
One possibility for the event is that a star in the disk of M31 gravitationally lensed a red giant also in the disk. The lensing star would have a mass between {{solar mass|0.02}} and {{solar mass|3.6}} with the most likely value near {{solar mass|0.5}}. In this case the lens profile makes it likely{{how?|date=July 2021}} that the star has a planet.{{Cite web|url=https://exoplanet.eu/catalog/pa_99_n2_b--556/|title=The Extrasolar Planet Encyclopaedia — PA-99-N2 b|date=1995 |work=Extrasolar Planets Encyclopaedia|access-date=2017-07-30}}{{cite conference|doi=10.1142/9789814374552_0433|arxiv=1001.2105|chapter=Detection of Exoplanets in M31 with Pixel-Lensing: The Event Pa-99-N2 Case|title = The Twelfth Marcel Grossmann Meeting|journal=The Twelfth Marcel Grossmann Meeting: On Recent Developments in Theoretical and Experimental General Relativity|pages=2191|year = 2012|last1 = Ingrosso|first1 = G.|last2=Paolis|first2=F. DE|last3=Novati|first3=S. Calchi|last4=Jetzer|first4=PH.|last5=Nucita|first5=A. A.|last6=Zakharov|first6=A. F.|isbn=978-981-4374-51-4|bibcode=2012mgm..conf.2191I}}
Possible exoplanet
The possible exoplanet would have a mass of 6.34 Jupiter mass. If confirmed, it would be the first exoplanet found in another galaxy.{{cite journal|last1=An|first1=Jin H.|last2=Evans|first2=N. W.|last3=Kerins|first3=E.|last4=Baillon|first4=P.|last5=Calchi Novati|first5=S.|last6=Carr|first6=B. J.|last7=Creze|first7=M.|last8=Giraud‐Heraud|first8=Y.|last9=Gould|first9=A.|last10=Hewett|first10=P.|last11=Jetzer|first11=Ph.|last12=Kaplan|first12=J.|last13=Paulin‐Henriksson|first13=S.|last14=Smartt|first14=S. J.|last15=Tsapras|first15=Y.|last16=Valls‐Gabaud|first16=D.|title=The Anomaly in the Candidate Microlensing Event PA‐99‐N2|journal=The Astrophysical Journal|date=February 2004|volume=601|issue=2|pages=845–857|doi=10.1086/380820|bibcode=2004ApJ...601..845A|arxiv = astro-ph/0310457 |s2cid=8312033}} A similar event was seen in 1996 when a team of astronomers discovered an anomalous fluctuation in the Twin Quasar's lightcurve that seemed to be caused by a planet approximately three Earth masses in size in the quasar's lensing galaxy YGKOW G1. (However, the results remain speculative because the chance alignment that led to its discovery will never happen again; if that exoplanet could be confirmed, it would be the most distant known planet, 2.58 Million ly away.){{cite magazine|magazine=New Scientist|issue=2037|url=https://www.newscientist.com/article/mg15120372.600-science--do-alien-worlds-throng-faraway-galaxy.html|title=Do alien worlds throng faraway galaxy?|author=Govert Schilling|date=6 July 1996}}
{{OrbitboxPlanet begin
}}
{{OrbitboxPlanet hypothetical
| exoplanet = b
| mass = 6.34
}}
{{Orbitbox end}}
References
{{Stars of Andromeda}}
{{DEFAULTSORT:PA-99-N2}}
Category:Andromeda (constellation)
Category:Gravitational lensing
{{exoplanet-stub}}